1. Field of Invention
The present invention relates generally to a surgical knot instrument, specifically to a device that transfers and tightens a knotted suture from outside to inside a patient's body during a surgery in order to attach severed and non-severed internal tissues.
2. Prior Art
Placing a surgical knot of a suture during an endoscopic procedure such as laparoscopy, pelviscopy, thoracoscopy, and arthroscopy can be difficult because access to the surgical site must be obtained through a number of hollow entry-exit access tubes, called “access ports” in the medical field, each inserted into a patient's body through a small incision in lieu of a traditional open large incision used for surgical entry. Typically, a surgeon inserts a needle attached to a suture through an access port using a needle holding instrument, passes the needle through a portion of severed or non-severed internal tissues at an internal surgical site, and makes a knot in the suture using a grasping instrument extending through a second access port and the needle holding instrument. One of these instruments is replaced with a cutting instrument to cut the needle off the suture so that it can be taken out.
These skills are difficult to learn and tying the knot is particularly challenging. The knot can be too loose, too tight, and tear out of the tissues if improper tension is placed on the suture when tying the knot. Furthermore, the needle can get lost inside the patient's body if it breaks off the suture when the knot is being tied or if it drops off the instrument when it is being taken out of the access port.
To alleviate this difficulty, a multitude of knot pushers are available that transfer a knot tied outside the patient's body (extracorporeal) to the surgical site inside the body (intracorporeal) through the access port. In a typical surgical procedure using a knot pusher, the suture is stitched between two portions of a severed or non-severed tissue with both ends of the suture extending out of the access port. The surgeon ties the suture into a slidable knot extracorporeally and a working end of a knot pusher is placed behind the knot. The knot pusher's working end is pushed against the knot while the surgeon pulls on both ends of the suture with equal tension in the opposite direction. This transfers the knot down the access port and tightens it at the surgical site. These steps can be repeated so that a plurality of knots can be placed.
U.S. Pat. No. 3,871,379 to Clarke (1975) describes a knot pusher with a C-shaped working end that captures and slides the knot to the surgical site where it is tightened by pulling on the suture ends. Although this device can transfer the knot, the knot rests deeply within the working (distal) end of the knot pusher and this can hinder the knot from being cinched tightly against the tissue. In addition, the knot can drop off, slide sideways out of position, and jam at the working end.
A number of knot pushers have a working end with a groove, a notch, a cut-out, and a slot that transfer and tighten the knot directly against the tissue. For example, U.S. Pat. No. 2,595,086 to Larzelere (1952) discloses a grooved ring, U.S. Pat. No. 5,234,444 to Christoudias (1993) shows a pusher with a pair of grooves, U.S. Pat. No. 5,403,330 to Tuason (1995) demonstrates a plurality of cut-outs, U.S. Pat. No. 5,201,744 to Jones (1993) has a notch and a magnetized slot, U.S. Pat. No. 5,549,618 to Fleenor et al. (1996) shows a slotted knot pusher assembly, U.S. Pat. No. 5,217,471 to Burkhart (1993) describes a recessed notched guide and a jawed knot holder, and U.S. Pat. No. 6,221,084 to Fleenor (2001) discloses a notched sleeve at the working end. Although these knot pushers can transfer the knot directly against the tissue, the knot may drop off, lock up, or slide sideways off the working end.
A number of knot pushers have a hook, an eyelet, a slot, or a groove that encircle and hold the suture at a working end to minimize the problem of dropping the knot. However, their designs have numerous disadvantages. For example, U.S. Pat. No. 6,258,106 to Leonard (2001) describes a pusher with a slotted J-hooked working end and U.S. Pat. No. 6,045,561 to Marshall et al. (2000) show one with a slotted circular working end. Both devices releasably capture one end of suture, transfer the knot, and cinch it to the tissue. However, the knot tends to slide sideways off the working end.
U.S. Pat. No. 5,176,691 to Pierce (1993) discloses twelve different knot pushers. One device has a working end with a pair of suture holding eyelets and a face to push the knot, another has a cylinder with a pair of eyelets that slides on a rod, another has a pair of two elongated movable parts where each has an eyelet, another has a pair of elongated moving members where each has an eyelet, and another has a pair of grooves with a transverse hole to insert suture. Pierce states that binding and jamming of the knot may occur in the eyelets or holes so he recommends that the surgeon “apply tension alternately to the suture ends in a reciprocating, see-sawing, or jiggling motion.” However, this can damage the suture or the knot. Also, the frictional forces between the knot and the face that pushes it can restrict knot transfer, damage the knot, and tear suture out of the surgical site. In addition, the surgeon rust take extra operating time to repetitively and tediously remove one end of suture out of an eyelet, tie the knot, and re-thread the suture in the eyelet for all knots subsequent to the first.
Pierce discloses two other devices that have either a pair of wedge-shaped bars or a rotating sleeve that open and close a pair of eyelets. However, these bars and sleeves can be difficult to operate, and can jam, damage, or cut the suture.
Pierce also discloses a knot pusher that has a ring that holds the suture in a pair of grooves. However, the knot may slide to the side, lock in the ring, or fall off the working end if the ring dislodges or breaks. Another device has a removable working end and a mechanism to snap a suture in a pair of eyelets that can fall off inside a patient. Pierce describes two more devices that have a face and a number of eyelets, of which one has a hollow interior. Both are designed to push a knot sideways. However, they can be awkward to use, lock the knot, and difficult to place a tight knot. Another has a working end with a sliding suture cutting tube that can malfunction and inadvertently cut the knot or tissue.
U.S. Pat. No. 5,292,327 to Dodd et al. (1994), discloses a knot pusher with a concave eyelet that pushes the knot. However, the knot may lock, fray or break, and the suture can tear out of the tissue.
U.S. Pat. No. 5,324,298 to Phillips, et al. (1994) shows a knot pusher with a working end that has a slotted groove and a locking sleeve with a slit. Alignment of the slot, slit, knot, and suture can be difficult; and a tip that “bears against the slip-knot” may damage or lock the knot.
U.S. Pat. No. 5,423,837 to Mericle, et al. (1995) discloses a knot pusher with a working end that has a slotted hole that pushes against the knot that can become locked and a spring based suture-cutting shaft that can malfunction and inadvertently cut tissue.
U.S. Pat. No. 5,752,964 to Mericle (1998) describes a knot pusher with a flattened working end that has an eyelet between a pair of resilient opposing jaws with a spring based blade to cut suture where pulling on the suture as the sides of the jaws are pushed against the tissue tightens the knot. However, the knot can slide into the eyelet and lock in the jaws.
U.S. Pat. No. 5,797,929 to Andreas, et al. (1998) describes a shaft with a closable slot that pushes the knot. However, the knot can fall out of the slot if it opens or can lock in the slot during knot transfer.
U.S. Pat. No. 4,602,635 to Mulhollan et al. (1986) shows a knot pusher with a tunneled oblique flat working end and U.S. Pat. No. 5,269,791 to Mayzels et al. (1993) describes a knot pusher with a working end that has a spiraling coil and a terminal eyelet. Both devices cinch the knot by pulling the suture and pushing the working end against the knot. However, both devices can inadvertently lock the knot before it is fully transferred to the surgical site and tear the suture out of the tissue.
A number of knot pushers are designed where the suture is coiled around a working end, manipulated off the knot pusher, and tightened at the surgical site. For example, U.S. Pat. No. 5,397,326 to Magnum (1995) shows a pair of U-shaped clefts and a spiral channel to hold suture at an end of a knot pusher. Magnum states that suture may drop off the clefts or slip out of the channel of this device.
U.S. Pat. No. 5,741,280 to Fleenor (1998) demonstrates a more complicated knot pusher assembly where a knot carrier tube with concentric ferrules deploys knots that can tangle and tear the suture out of the tissue since both ends of suture are “tensioned to form a complete knotted loop.”
Knot tiers comprised of complex mechanical moving parts have been described. U.S. Pat. No. 4,961,741 to Hayhurst (1990) discloses a suturing device where a leading member slides the first knot to the surgical site and opens to permit a trailing member to pass through it so that a second knot is placed.
U.S. Pat. No. 5,192,287 to Fournier (1993) discloses a complex mechanical device that has two shaft members, an actuation mechanism, and a set of suture holding grooves at the working end.
U.S. Pat. Nos. 5,084,058 (1992), 5,163,946 (1992) to Li, and U.S. Pat. No. 5,133,723 to Li, et al. (1992) describe a series of complex mechanical pegs for releasably supporting a plurality of knots, a knot rundown tool with a pair of grooves that has a slot for removing throws from the pegs, and a third device that blindly cuts the suture ends.
Although these devices are useful, the complex construction and moving parts make them more vulnerable to the effects of wear and tear that may result in breakage of parts where the device can stop working or leave broken metal pieces in the patient's body which must be retrieved. Furthermore, any malfunction of these devices during surgery can damage the suture, the knot, and the tissue being sutured.
In addition to knot pushers, knot pullers for intracorporeal knot tying have been devised. For example, U.S. Pat. No. 5,693,061 to Pierce et al. (1997) discloses a knot puller where a pair of appendages hold a length of suture between them and the knot is tied by the applying tension to the suture adjacent the knot. Applying tension can tear out the suture or damage the tissue being tied.
Thus, all prior art devices of extracorporeal knot pushers that I am aware of have one or more of the following disadvantages: (a) knots can drop off, slide to the side, and lock up in the working end; (b) knots or suture can fray and break from the frictional resistance between the suture or knot and the working end during knot transfer and tightening of the knot; (c) the suture can tangle intracorporeally and become difficult to tighten; (d) knots can be cinched loosely so that tissue approximation is unsatisfactory; (e) knots can be torn out of the tissue from pulling on the suture in the opposite direction from the tissue being sutured; and (f) due to complexity, they can break apart, stop functioning, or malfunction causing damage to the suture or knot, resulting in bodily injury, or requiring retrieval of broken parts.